This invention relates to foundation units, and more particularly to a variable spring surface deck for a foundation, as well as a foundation having such a deck. The deck allows for spacial variation of and various amounts of spring support for the foundation.
Foundation units are found in many forms. The typical “box spring” is composed of a flat wooden bottom frame, a grid wire top surface, and a series of transverse rows and longitudinal columns of coil springs attached between the grid wire and the wooden frame. Top padding and a cover are then applied to give the foundation a finished look.
An alternative form of a box spring foundation is found in U.S. Pat. No. 4,074,372. In this patent, a wooden frame of substantially greater depth is employed, which increases the strength of the foundation and reduces the depth of the coil springs required. Similar to the typical “box spring”, it is finished with padding and a cover.
Other, less expensive foundations are fabricated using only a wooden or rigid wire frame. A build up of one or more inches of padding material is used to cushion the top of the foundation unit, and a cover is applied in a usual fashion. One type of rigid wire frame foundation is disclosed in U.S. Pat. No. 4,377,279.
A substantial disadvantage of all prior art foundations is either difficulty or inability of varying the surface support of the foundation. As a result, many different models of the same or a similar foundation must be provided if varying support is desired.